Seismic gas shut-off valve



FIG. 1 is a front elevational view of a seismic gas shut-off valve showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is an elevational view of the left side thereof;

FIG. 5 is an elevational view of the right side thereof; and

FIG. 6 is a rear elevational view thereof. 

The ornamental design for a seismic gas shut-off valve, as shown and described. 